Residues of hormones and anabolic steroids in foods such as meat or milk provide a potential health risk to consumers. Therefore, R-Biopharm offers test systems for the detection of natural and synthetic hormones and steroids.

Hormones are endogenous biochemical messengers which are transported through the bloodstream to their target organs. Besides natural sex hormones, synthetic steroids and beta-agonists can be used in livestock breeding to improve the average weight gain and the meat/fat-ratio. As a result of inappropriate or illegal use, residues in food of animal origin such as meat or milk may occur and bear a direct health risk to consumers. Additionally, the entry of hormonal active substances into surface and ground water by manure can have an impact on aquatic ecosystems. Through drinking water and fish consumption, hormone residues could also re-enter the food chain.

In the European Union, the use of hormones and anabolic steroids as growth-promoting substances in animal breeding is completely banned and residues are monitored under surveillance programs (Directives 96/22/EC, 2008/97/EC and 2003/74/EC). However, the therapeutic use of certain hormones for veterinary purposes is permitted. In contrast, outside of Europe, hormones and anabolics can be legally used as fattening agents, because the local authorities assessed their usage as risk-free.


Androgens are natural or synthetic steroid hormones that stimulate or control the development and maintenance of male characteristics by binding to androgen receptors. The group of androgens includes many synthetic molecules in addition to natural testosterone. If animals are treated with androgens, drug residues may remain in the animal’s meat and milk. Our test systems can reliably detect androgen residues.


Testosterone is a natural male steroid hormone that stimulates the development and maintenance of male characteristics. Because of the illegal use as resource in cattle fattening, for example in the German residue control plan, the legally demanded detection limit in bovine plasma for HPLC-SP and GC-MS is < 0.1 μg/kg (ppb). For screening purposes the sensitive and cost effective RIDASCREEN ELISA can be used. The application of this method in bovine plasma has a detection limit of 0.02 µg/kg. The incubation time of the test is 2 hrs 30 min. which enables a high throughput and a fast response.


The anabolic effects of methyltestosterone (17α-methyltestosterone) are comparable to those of testosterone, which is a natural male sexual hormone. Methyltestosterone is a synthetic steroid hormone and as testosterone illegally used in cattle fattening. Besides this, it is commonly used by fish farmers for sex reversal in fish to obtain fast-growing-all-male populations for economic gains. The ELISA system is a rapid and cost-effective screening method to control abuse of methyltestosterone by governmental agencies and laboratories. For confirmation physicochemical methods like HPLC and GC/MS are applicable. In most EC countries urine is chosen as the matrix to screen for the presence of ethinylestradiol or other anabolic steroids.


The anabolic steroid 19-nortestosterone is one of the most frequently found growth promoters. The anabolic effects of 19-Nortestosterone are comparable to those of testosterone, but with less androgenic effects. In Germany, 19-Nortestosterone-decanoate and -laureate are permitted for veterinary use in defined applications. However, the illegal use of 19-Nortestosterone as doping agents in high performance sports or horse sports are far more common. Some years ago, the increasing application of illegal cocktails as a fattening resource in calf fattening was reported. These cocktails usually contained 19-Nortestosterone-ester. Especially in male pigs and pregnant cows endogenous 19-nortestosterone can be detected.


Trenbolone is a xenobiotic, efficient anabolic steroid with strong androgenic activity. Genotoxic activity of this substance is suspected, however not scientifically proven yet. However, trenbolone in increased concentrations induced cell transformation in a test using “syrian hamster embryonal cells”, and reacted weakly positive in the Ames-test. To increase its effective half-life, trenbolone is administered as an ester conjugate such as trenbolone acetate. Plasma lipases then cleave the ester group in the bloodstream leaving free trenbolone. The use of this compound to increase muscle growth and appetite in cattle breeding is prohibited in the EU. For high throughput screening of samples, the ELISA test system is an excellent test which can be used in a variety of matrices.


Estrogens (or oestrogens) are primary female sex hormones and play an important role in the regulation of many physiological processes of the reproductive system, such as ovulation, fertilization, implantation of the embryo and lactation. They can be produced synthetically and are used as a medication. Some estrogens are used as steroids. If animals are treated with estrogens, drug residues may remain in the animal’s meat and milk. Our reliable test systems can detect estrogen residues.

Diethylstilbestrol (DES)

Diethylstilbestrol (DES) and hexestrol are substances of the group of stilbenes, which are very efficient anabolic steroids, combined with a strong estrogenic activity. DES affects weight gain and feed conversion efficiency if administered to animals used for meat production. These phenomena are observed in cattle, chicken and lambs. The use of anabolic drugs for these purposes has been forbidden in the EU since 1986. The use of DES is specifically forbidden in all countries due to its carcinogenic properties. For the analysis of anabolic steroids HPLC and GC/MS are described as physicochemical methods. Immunological assays like RIA or EIA are very often used as screening methods.


17ß-Estradiol is a natural sexual hormone. The levels of 17β-estradiol in bovine plasma from peripheral blood are very low. In calves not more than 1 – 2 pg/ml are present and in cycling females the concentration of 17β-estradiol is 1 – 5 pg/ml. Only in plasma of pregnant animals or in plasma of animals illegally treated with anabolic agents, levels in the range of 100 to 1000 pg/ml can be found.


Ethinylestradiol is a synthetic sexual hormone which is, like all other natural or synthetic steroid  hormones, prohibited for use as resource in fattening in the European Community since 1988. The ELISA system is a rapid and cost-effective screening method to control abuse of ethinylestradiol. In most EC countries urine is chosen as the matrix to screen for the presence of ethinylestradiol or other anabolic steroids.


The oestrogenic anabolic agent zeranol (a-Zearalanol) is derived from the mycotoxin zearalenone. It is used to increase the average daily live-weight gain in ruminants and to improve the food conversion efficiency. However, this compound has not been authorized as fattening adjuvant in the EU. The synthetic compound zeranol possesses about three times the estrogenic activity of zearalenone. Besides its anabolic effects, zeranol causes the clinical signs of hyperestrogenism, particularly reduced fertility and disorders in development. It is thus not impossible that zeranol residues in edible tissues, after use in illegal practice, may lead to a risk for consumers.


Gestagens (also known as progestogens or progestagens) are female sex hormones and a class of steroid hormones. They are sometimes used as growth promoters in livestock. When animals are treated with gestagens, drug residues may remain in the animal’s meat and milk. With our test systems, you can reliably detect gestagen residues.

Acetyl gestagenes

Medroxyprogesterone acetate (MPA), 17α-acetoxyprogesterone, megestrol acetate and chlormadinone acetate belong to the group of acetyl gestagenes. Acetyl gestagenes are known to increase the efficiency of animal production and have been used in illegal cocktails for calf fattening in the past. However, these substances are not permitted as resources for animal fattening. Some studies have shown that the peak concentrations of acetyl gestagene residues can be observed in fat tissue. MPA, for instance, can be detected in plasma only a few days past application but it cannot be detected with accuracy in urine. After the application of MPA to calves, high concentrations of non-metabolized MPA can be detected in fat, even after 19 days.

Melengestrol acetate

Synthetic gestagens can be used for estrus inhibition or synchronisation after break off and improvement of fertility. In addition, one of these substances, melengestrol acetate (MLGA), is a licensed growth promoting feed additive for heifers in the USA and Canada. The admitted dose is 0.5 mg per day and head, given as a feed premix. Its mode of anabolic action is unclear, but it stimulates the ovarian synthesis of the endogenous anabolic steroid estradiol and that may have androgenic side effects. MLGA belongs to the most active synthetic gestagens. Its oral bioactivity is about 10 or 100 times higher than the activities of the gestagens chlormadinone acetate (CMA) or medroxyprogesterone acetate (MPA), resp. If given parenterally, the hormonal activity of MLGA is still 125 times higher than the one of progesterone. Due to its strongly lipophilic properties, MLGA is accumulated in fat 200-fold higher than in blood plasma. In the European Union, the use of sexual hormones for growth promoting purposes is generally forbidden since 1988, and also the import of meat from hormone treated cattle into the EU is prohibited.


β-Agonists are synthetic derivatives of the naturally occurring catecholamines. They are used as medication. When animals are treated with ß-agonists, drug residues may remain in the animal’s meat and milk. It has been known that β-agonists are suitable for use as performance improvers within the field of livestock production. In particular, the meat/fat ratio in fattened animals can be improved or the growth may be accelerated. However, such compounds have not been approved in the EU for use as fattening adjuvants (growth promoters) up to now. In addition to lipolytic and anabolic effects, β-agonists have relaxing effects on non-striated musculature. Thus, they can be used as anti-asthmatic and tocolytic agents. It is possible that β-agonists residues, after use in illegal practice, may lead to a risk for consumers. Therefore, the use of β-agonists use in food production was prohibited.


Clenbuterol belongs to the group of β-agonists. In comparison to therapeutic use, clenbuterol is administered at 5 to 10 time’s higher dosages when employed as a fattening adjuvant. Therefore, it is possible that clenbuterol residues, after use in illegal practice, may lead to a risk for consumers.


Ractopamine belongs to the group of β-agonists. As a performance improver within the field of livestock production, ractopamine reduces fat, increases average daily weight gain, and improves the feed conversion ratio (FCR) in fattened animals. It is possible that ractopamine residues, after use in illegal practice, may lead to a risk for consumers. Consequently, the use of ractopamine has been banned in most countries.

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